Leading tests of the Standard Model, like measurements of the electron electric dipole moment or of matter-antimatter asymmetry, are built upon our ability to laser-cool atoms and molecules to ultracold temperatures. Unfortunately, laser-cooling remains limited to a minute collection of species with very specific electronic structures. To include more species, such as polyatomic molecules or exotic atoms like antihydrogen, new cooling methods are needed. Here we demonstrate a method based on Sisyphus cooling that was proposed for laser-cooling antihydrogen. In our implementation, atoms are selectively excited to an electronic state whose energy is spatially modulated by an optical lattice, and the ensuing spontaneous decay completes one Sisyphus cycle. We show that this method eliminates many constraints of traditional radiation-pressure-based approaches, while providing similar atom numbers with lower temperatures. This laser-cooling method can be instrumental in bringing new exotic species and molecules to the ultracold regime.

• Received 18 October 2018
• Revised 24 June 2019

DOI:https://doi.org/10.1103/PhysRevA.100.023401